Field of the Invention
The present invention relates to a method and device for calibrating a transmission path and reception path of a group antenna with an adaptive radiation pattern. A group antenna with an adaptive radiation pattern is, e.g., described in European Patent Document EP 0 578 060 A2 or German Patent Document DE 195 35 441 A1. The radiation pattern or radiation variations of the transmission and/or reception characteristics are measured with the help of a radiation pattern network, in which the transmitted and received signals of the individual antenna elements are multiplied according to the desired antenna characteristics with different weighting factors. This type of group antenna with an adaptive radiation pattern can for example be used in a cellular mobile radio system or a point-to-multipoint radio broadcast system.
The radiation pattern can be corrupted or adulterated by errors in the signal path of the individual antenna elements. Errors in the signal paths can be caused, e.g., by production tolerances or temperature drift or alterations, etc. Degradation of the desired radiation pattern can be reduced by calibrating the signal path between the radiation pattern network and the individual antenna elements.